Apparatus and method for sensor deployment and fixation

ABSTRACT

A delivery system for fixation of an implant assembly having an intracorporeal device at a deployment site using an anchoring structure. This invention provides an implant assembly having an anchor for fixation within a vessel. The anchoring structure adapted to be delivered via a catheter.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. Utilityapplication Ser. No. 11/180,840, filed Jul. 13, 2005, which claims thebenefit of U.S. Provisional Application No. 60/658,358, filed Mar. 3,2005 and to U.S. Provisional Application No. 60/662,210, filed Mar. 14,2005, which applications are herein incorporated by reference in theirentirety.

FIELD OF THE INVENTION

This invention relates generally to implantation of intracorporealdevices into vessels, and to fixing the devices, either permanently ortemporarily, within the vessel.

BACKGROUND

In recent years, the long-sought goal of implantable biosensors hasbegun to see realization and, in some cases, clinical use. As thisconcept has seen continued research and development, issues regardingintracorporeal fixation of the sensor have come to light. Particularlywithin blood vessels, the sensor is subjected to a continuous, pulsatileflow. This is a difficult environment in which to secure a sensor orother apparatus reliably without unduly restricting blood flow orimpairing the vessel wall. One major vessel of interest in the realm ofcardiology is the pulmonary artery. The pulmonary artery is aparticularly challenging location in which to secure an intracorporealdevice because, in addition to the above considerations, the vessel isespecially thin, compliant and prone to perforation.

Design considerations for an ideal fixation device intended forintravascular fixation are outlined as follows. The fixation deviceshould be passive and maintain a separation distance between the sensorand the vessel wall. The deployed size and radial strength of the deviceshould be sufficient to prevent its migration into vessels that would beoccluded by the dimensions of the sensor while creating minimal stressconcentrations where the fixation device contacts the vessel wall.Alternatively, intracorporeal devices can be designed sufficiently smallin size so that when deployed in organs or regions with sufficientlyredundant blood flow, the device can embolize on its own without harmingthe organ or the host. Finally, the fixation device should besufficiently versatile as not to depend, within physiologically relevantranges, on the size of the vessel in order to maintain its position.

There have been attempts to create devices intended to holdintracorporeal devices fixedly within vessels. Several such attempts aredescribed in patent publication number US 2004/0044393 and in Europeanpatent application number EP0928598. These attempts fall short ofmeeting all of the necessary requirements outlined above.

Prior art devices include a self-expansible stent on which anintracorporeal device is mounted. This stent maintains a known lengthwhen implanted in a vessel where only the approximate diameter can bedetermined. Other devices and methods include fixation of a sensor in abodily lumen, in which the sensor support is coupled to a fixationdevice. The fixation device is a stent or ring, has a sensor supportcoupled thereto and is intended to be sutured to the vessel wall or heldin place by plastically deforming the structure using a ballooncatheter. The ring is essentially a stent with an abbreviated length andsuffers from the same shortcomings as traditional stent devices.

For example, a stent is designed with mechanical characteristics thatenable it to hold open diseased vessels post dilation. Therefore, theradial strength of the stent is greater than the inward radial forcesexerted during vessel recoil. This primary requirement leads to amismatch in compliance, with that of the stent dominating. Subsequently,stress concentrations are created at the interface of the stent andvessel. These stress concentrations are greatest at the terminal ends ofthe stent where there is an abrupt transition in stiffness between thestented and unstented segments of the vessel. As undiseased vessels areusually more compliant compared to diseased ones, this problem isamplified when placing a stent in healthy vasculature. Along similarlines, accurate stent sizing in the vessel is critical, especially inthe case of the pulmonary artery. Thus, the physician must be consciousof the particulars of vessel compliance, recoil and stent radialstrength in order to choose the best stent expanded diameter for a givenvessel. This determination presents its own set of challenges andrequires an unnecessary increase in complexity. Therefore, the use of astent in order to maintain an intracorporeal device in a vessel is notoptimal.

Thus, a need exists for devices and methods for fixing intracorporealdevices which satisfy the design requirements described herein.Furthermore, a need exists to deliver and fix such devices in a safe andpredictable manner.

SUMMARY

Stated generally, this invention comprises an apparatus and method ofdeployment and fixation of an implant assembly by using a deliveryapparatus to deliver an intracorporeal device to a deployment site andfixation of the device using an anchoring structure. The intracorporealdevice may be either a wired or a wireless device.

Thus, it is an aspect of this invention to provide an implant assemblyhaving an anchor for fixation within a vessel.

A further aspect of this invention to provide an anchoring structureadapted to be delivered via a delivery apparatus, such as a catheter.

Other objects, features, and advantages of the present invention willbecome apparent upon reading the following specification, when taken inconjunction with the drawings and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a first embodiment of an implant assemblyof this invention having two opposed wire loops.

FIG. 2 is a top view of the implant assembly of FIG. 1.

FIG. 3 is a side view of the implant assembly of FIG. 1 fixed in avessel.

FIG. 4 is a top view of a second embodiment of an implant assembly ofthe invention having opposed wire loops.

FIG. 5 is a top view of the implant assembly of FIG. 4 fixed in avessel.

FIG. 6 is a top view of a third embodiment of an implant assembly ofthis invention having two opposed wire loops.

FIG. 7 is an isometric view of the implant assembly of FIG. 6.

FIG. 8 is an isometric view of the implant assembly of FIG. 6 fixed in avessel.

FIG. 9 is a top view of a fourth embodiment of an implant assembly ofthis invention having opposed wire loops.

FIG. 10 is an isometric view of the implant assembly of FIG. 9.

FIG. 11 is an isometric view of the implant assembly of FIG. 9 fixed ina vessel.

FIG. 12 is an isometric view of a fourth embodiment of an implantassembly of this invention having a radial wire array expansiblestructure.

FIG. 13 is an isometric view of a fifth embodiment of an implantassembly having an alternative radial wire array.

FIG. 14 is an isometric view of a sixth embodiment of an implantassembly of this invention having two radial wire array expansiblestructures.

FIG. 15 is an isometric view of the implant assembly of FIG. 12 fixed ina vessel.

FIG. 16 is an isometric view of a seventh embodiment of an implantassembly of this invention having a radial wire array expansiblestructure.

FIG. 17 is an isometric view of the implant assembly of FIG. 16 fixed ina vessel.

FIG. 18 is an isometric view of an eighth embodiment of an implantassembly of this invention having a daisy petal wire expansiblestructure.

FIG. 19 is an isometric view of a ninth embodiment of an implantassembly of this invention having a daisy petal expansible structure oneach end of an intracorporeal device.

FIG. 20 is an isometric view of a tenth embodiment of an implantassembly of this invention having a daisy petal wire expansiblestructure.

FIG. 21 is an isometric view of an eleventh embodiment of an implantassembly of this invention having a daisy petal wire expansiblestructure.

FIG. 22 is an isometric view of the implant assembly of FIG. 18 fixed ina vessel.

FIG. 23 is a side cross-sectional view of a delivery apparatus of thisinvention.

FIG. 24 is a side view of a tether wire of the delivery apparatus ofthis invention.

FIG. 25 is a side view of a core wire of the delivery apparatus of thisinvention.

FIG. 26 is a side view of a guidewire of the delivery apparatus of thisinvention.

FIG. 27 is a side cross-sectional view of the delivery system of thisinvention comprising the components of FIGS. 23-26.

FIG. 28 is a side cross-sectional view of the delivery system of thisinvention comprising the components of FIGS. 23-26 and theintracorporeal device of FIGS. 4 and 5.

DETAILED DESCRIPTION

An implant assembly of this invention includes an intracorporeal deviceand an anchoring structure used to stabilize the intracorporeal devicein the body, such as in a vessel. Delivery systems of this invention areused to deploy and secure the implant assembly in a desired location ina vessel and include a delivery apparatus and an implant assembly. Theintracorporeal device may be a pressure sensor, further described below.The anchoring structure may be a structure capable of being introducedinto the body via a delivery apparatus, such as a catheter, and thenlodging within the vessel. Anchoring structures of this invention may beformed from metal or polymer, and may be in the form of a wirestructure. Wire structures of this invention may include structureincluding opposed wire loops, radial wire array structures, and daisypetal structures, all further described below.

All of the implant assemblies of this invention obstruct approximately50% or less of the cross-sectional area of the vessel in which itresides. Preferably, the implant assemblies obstruct 20% or less of thecross-sectional area of the vessel. Minimizing the obstruction of flowwithin the vessel allows the sensor to remain secured in position in avessel without creating significant impact to the flow within thevessel.

The intracorporeal device used to couple to the anchoring structuresdescribed below has a width of about 0.5 to about 4 mm, a height ofabout 0.5 to about 4 mm, and a length of about 0.5 to about 12 mm. Inone embodiment, the intracorporeal device has a width of 3.2 mm, aheight of 2 mm, and a length of 10 mm. Examples of such devices aredisclosed in commonly owned patents U.S. Pat. No. 6,855,115; and inco-pending, commonly owned applications Ser. Nos. 10/054,671;10/886,829; 10/215,377; 10/215,379; 10/943,772 incorporated herein byreference.

Wire Loop Structures

One implant assembly of this invention adapted for deployment andfixation within a vessel includes an intracorporeal device and a wirestructure having wire loops. The loops may traverse the length of thedevice or may be limited to one end of the device. As shown in FIGS.1-3, one embodiment of an implant assembly 30 having a double loopstructure 32 includes a wire 34 attached to an intracorporeal device 36at an anchor point (not shown). The wire 34 is threaded through an endof the intracorporeal device 36 at a hole 38. The anchor point is formedby crimping a piece of metal to the wire and trimming off the excesswire, so that the crimped-on metal comprises the terminal end of thewire. This metal end also provides a radiopaque marker for fluoroscopicvisualization of the device.

After the wire 34 is threaded through the hole 38 on one end of thedevice, the wire is pulled with sufficient force to bury the anchorfixedly into the silicone coating of the intracorporeal device. The wire34 is then looped around to form the 20 double loop configuration 32.The second free end is also inserted under the coating and the anchor isburied in the coating to fix the anchor. In this manner, the ends of thewire are inserted under the coating of the intracorporeal device 36 andaway from the sensor.

Upon deployment of the implant assembly 30, the wire 34 contacts theinner surface 40 of the wall of the vessel 42, as shown in FIG. 3. Thearrow shown in FIG. 3 indicates the direction of blood flow.

In an alternative embodiment, shown in FIGS. 4 and 5, the loop structurehas a “figure eight” shape. Implant assembly 31 having a double loopstructure 33 includes a wire 35 attached to sensor body 37 at an anchorpoint (not shown). The ends of the wire 35 are inserted under thecoating of the sensor body 37 and away from the sensor as described inthe previous example. Upon deployment of the implant assembly 31, thewire 35 contacts the inner surface 41 of the wall of the vessel 43, asshown in FIG. 5. The arrow shown in FIG. 5 indicates the direction ofblood flow.

According to one embodiment, the opposed loop structure is constructedof a single wire. In an alternative embodiment, the opposed loopstructure is constructed of more than one wire.

In alternative embodiments, shown in FIGS. 6-8 and 9-11, the structureincludes a plurality of wire loops 44 encircling an intracorporealdevice 46. The wire 48 is threaded from end to end in a circularfashion, through one or more holes 50 located on each end of the sensor,to form the loops. Upon completion of the loop structure, the free endof the wire is used to create another anchor as described above. Thesecond free end is then pulled back into the silicone coating withsufficient force to bury the second anchor fixedly in the siliconecoating. The location of the second anchor lies on the opposite side ofthe sensor from the first anchor. The wire loops are then arranged bymechanical means to create wire members that are substantially evenlydistributed radially around the longitudinal axis of the sensor.

The wire loops may be attached to the intracorporeal device 40 bythreading through one hole 50 located near the edge of the device 46 asreferenced to the longitudinal axis of the device 46, as shown in FIG.6. Alternatively, the wire loops may be attached to the intracorporealdevice 46 by threading through two holes 50 located near each edge ofthe device 46, as shown in FIG. 9. Upon deployment of the implantassembly, each configuration contacts the inner surface 52 of the wallof the vessel 54, as shown in FIGS. 8 and 11. The arrows shown in FIGS.8 and 11 indicate the direction of blood flow.

The wire diameter of the anchoring structure lies in the range of about0.001 to about 0.015 inches. The material comprising the wire can be anybiocompatible material known in the art that possess sufficient elasticproperties to be useful for the purpose at hand. The material may be ametal, such as nitinol, stainless steel, eligiloy, cobalt chrome alloys,or any other suitable metal. In a further embodiment, the biocompatiblewire is coated with a dielectric material, such as, but not limited to,PTFE, polyurethane, parylene and diamond-like carbon (DLC) so as not topose electromagnetic interference with the function of theintracorporeal device when the device comprises an RF sensor.

Radial Wire Array Structures

Another implant assembly according to this invention includes anintracorporeal device and an anchoring structure having a substantiallyparabolic-shaped profile, as shown in FIGS. 12-17. As illustrated in theFigures, an implant assembly 58 includes an intracorporeal device 60 anda radial wire array 62, which includes wire members 64. Members 62 maybe attached to the intracorporeal device 60 at an anchor point, asdescribed above.

The radial wire array 62 can be attached to the intracorporeal device 60by threading the wire members 64 through one hole 66 located near theedge of the intracorporeal device 60, as shown in FIG. 12.Alternatively, the radial wire array 62 can be attached to theintracorporeal device 60 by threading the wire members 64 through twoholes 66 located near the edge of the device 60 as shown in FIG. 16. Thewire end is press-fit into a silicone coating covering the surface ofthe device to secure the end. The radial wire array may be formed bycrimping a piece of metal at a point substantially midlength of the wirebundle and then threading the wire bundle through a hole near the edgeof the intracorporeal device, thus lodging the anchor within thesilicone material filling the hole. The anchor secures the end of theradial wire between the surface of the device and the silicone coatingcovering the surface of the device. The crimped metal anchor provides aradiopaque marker for fluoroscopic visualization of the device. Upondeployment of the implant assembly, the radial wire array 62 contactsthe inner surface 68 of the wall of the vessel 70, as shown in FIGS. 15and 17.

In one embodiment, the radial wire array is self-supporting, as a resultof the physical properties of the material. Alternatively, the radialwire array may include a mechanical expansion structure to support thearray to expand and contact the vessel wall. For example, a catheterballoon may be inflated to cause a wire structure to attain and maintainan expanded configuration.

The intracorporeal device 60 can be positioned outside a radial wirearray 62 so that one end 72 of the intracorporeal device 60 is fixed toa point at or near the apex of the radial wire array 62, as shown inFIG. 12. The intracorporeal device 60 can also be positioned inside theradial wire array so that one end of the device is fixed to a point ator near the apex of the radial wire array, as shown in FIG. 13. Inanother embodiment, the intracorporeal device may have two radial wirearrays 62 attached to the intracorporeal device 60 so that one end ofthe intracorporeal device is attached to the apex on the exterior of oneof the radial wire arrays and the opposing end of said device isattached to the apex on the interior of the second radial wire array, asshown in FIG. 14.

In one embodiment, the ends of the radial wire array may terminate withbarbs or hooks 74 as shown in FIGS. 12-15. The hooks 74 are turnedoutwardly with respect to the longitudinal axis of the parabolic profileof the radial wire array 62. The hooks or barbs disposed on the distalends of the members of the radial wire array prevent the implantassembly from being dislodged after the hooks or barbs have engaged thewalls of the vessel, as shown in FIG. 15. The hook or barb featuresshould be of sufficient size to achieve adequate device fixation withoutperforation or dissection of the vessel wall. Alternatively, the fit ofthe radial wires within the walls of the vessel may fix the device inthe vessel without the use of hooks or barbs, as shown in FIG. 17. Thearrows shown in FIGS. 15 and 17 indicate the direction of blood flow.

The wire diameter of the radial wire array lies in the range of about0.001 to about 0.015 inches. The material comprising the wire can be anybiocompatible metal known in the art that possess sufficient elasticproperties to be useful for the purpose at hand. The metal may benitinol, stainless steel, eligiloy, cobalt chrome alloys, or any othersuitable metal. The biocompatible wire can optionally be coated withPTFE so as not to pose electromagnetic interference with the function ofthe intracorporeal device when the device comprises an RF sensor.

Daisy Petal Structures

An implant assembly according to another aspect of this inventionincludes an intracorporeal device and an anchoring structure having adaisy petal shape, as shown in FIGS. 18-22. The implant assembly 76includes an intracorporeal device 78 and a daisy petal wire structure80, which contacts the inner surface 82 of the wall of the vessel 84, asshown in FIG. 22. The arrow shown in FIG. 22 indicates the direction ofblood flow.

The intracorporeal device has a proximal end 86, a distal end 88, and alongitudinal axis 90, as shown in FIG. 18. The daisy petal wirestructure 80 is positioned so that the structure lies in a plane normalto the longitudinal axis 90 of the intracorporeal device 78. The daisypetal wire structure 80 may be constructed of a single wire or of aplurality of wires. As shown in FIG. 18, the daisy petal wire structure80 includes a plurality of lobes 92. The structure may have either aneven or an odd number of lobes. As shown in FIG. 19, the intracorporealdevice 78 may have two daisy petal wire structures 80 attached to thedevice on opposing ends 94, 96 and located along the longitudinal axis90.

The daisy petal wire structure 80 may be attached to the intracorporealdevice 78 by threading through a hole 98 located near the edge of thedevice 78, as shown in FIG. 20. Alternatively, the daisy petal wirestructure 80 may be attached to the intracorporeal device 78 bythreading through two holes 98 located near the edge of the device 78,as shown in FIGS. 18 and 21.

In one embodiment, the daisy petal wire structure 80 is attached to theintracorporeal device at an anchor point. The anchor is made by crimpinga piece of metal to the wire and trimming off the excess wire, so thatthe crimped-on metal comprises the terminal end of the wire. This metalend also provides a radiopaque marker for fluoroscopic visualization ofthe device. The wire is threaded through the hole or holes on one end ofthe sensor and the wire is pulled with sufficient force to bury theanchor fixedly into the silicone coating. The wire is then threaded fromtop to bottom in a circular fashion, through the hole or holes locatedon the end of the sensor, to form the daisy petal structure. Uponcompletion of the daisy petal structure, the free end of the wire isused to create another anchor. The second free end is then pulled backinto the silicone coating with sufficient force to bury the secondanchor fixedly in the silicone coating. The wire loops are then arrangedby mechanical means to create wire members that are substantially evenlydistributed radially around the longitudinal axis • of the sensor.

The wire diameter in the present invention lies in the range of about0.001 to about 0.015 inches. The material comprising the wire can be anybiocompatible material known in the art that possess sufficient physicalproperties to be useful for the purpose at hand and such materials areobvious to one skilled in the art. As an example, in a disclosedembodiment, the material is a metal selected from the group comprisingnitinol, stainless steel, eligiloy, and cobalt chrome alloys.Optionally, the biocompatible wire may be coated with a dielectricmaterial such as, but not limited to, PTFE, polyurethane, parylene anddiamond-like carbon (DLC) so as not to pose electromagnetic interferencewith the function of the intracorporeal device when the device comprisesan RF sensor.

Delivery Systems and Methods

This invention provides a delivery system for securing, delivering anddeploying an implant assembly having an anchoring mechanism coupled toan intracorporeal device. Referring to FIGS. 23-26, the variouscomponents of the delivery system are shown individually. As shown inFIG. 23, the delivery apparatus 100 includes a main lumen 102 adapted toaccept a core wire 104 (FIG. 25) and a secondary lumen comprising afirst section 106A and a second section 106B and adapted to accept atether wire 108 (FIG. 24). The core wire 104, shown in FIG. 25, providescolumnar stiffness to the delivery assembly 100, thereby facilitatingadvancement of the delivery assembly through the vasculature.Additionally, the core wire 104 also prevents buckling of the deliveryassembly 100 when the tether wire is pulled proximally during theimplant assembly deployment. The core wire 104 has a decreasing diametertoward its distal end 105, providing gradual decrease in stiffness fromthe proximal to the distal end of the delivery assembly 100. The taperedcore wire 104 can extend past a guidewire aperture 112 in order toreinforce a potential kink point in the delivery apparatus 100 and tofacilitate the advancement of the guidewire into the vasculature. Thecore wire 104 is fixed in the main lumen 102 using adhesive,thermocompression, or any other suitable fixation mechanism. Fixation ofthe core wire 104 prevents the core wire from being disturbed by theguidewire 110, shown in FIG. 26, when the guidewire 110 enters the mainlumen 102 of the delivery apparatus 100 at the guidewire aperture 112 asshown in FIG. 27.

The tether wire 108, shown in FIG. 24, is slidably positioned within thefirst secondary lumen portion 106A and exits the first secondary lumenportion at an aperture 114 in the wall of the device. As shown in FIG.27, the tether wire 108 then passes through the coating of theintracorporeal device 30, exiting on the opposite side of the device.The free end 118 of the tether wire 108 enters the second portion 106Bof the secondary lumen at the aperture 109.

FIG. 28 shows an alternate embodiment of a delivery apparatus adapted todeploy the sensor 31 of FIGS. 4 and 5. Because of the length of the wireloops 35 of the sensor 31, the proximal and distal ends of the loopsmust be secured to the delivery apparatus so that, when the deliveryapparatus curves, the loops will follow the curvature of the deliveryapparatus. Toward that end, the secondary lumen of the deliveryapparatus of FIG. 28 is divided into four sections 106A-D. The tetherwire 108 exits the first section 106A of the secondary lumen and passesover and through wire loops 55 to attach the implant assembly 51 to thedelivery apparatus 100. The tether wire then enters the second portion106B of the secondary lumen. The tether wire then exits the secondportion 106B of the secondary lumen and passes through the coating ofthe sensor 31. The tether wire then enters the third portion 106C of thesecondary lumen. Next, the tether wire exits the third portion 106C ofthe secondary lumen, passes over the wire loop 35, and enters the fourthsection 106D of the secondary lumen. Note that with the proximal anddistal wire loops 35 thus secured to the delivery apparatus, it isoptional as to whether to pass the tether wire 106 through the coatingof the body of the sensor 31.

In yet another configuration, an outer sleeve may be provided toconstrain an expansible structure and is slidably positioned over thedouble lumen tube.

Deployment and fixation of an intracorporeal device may be accomplishedusing either active or passive fixation. In one embodiment, anintracorporeal device is delivered into the vessel and allowed to floatin the blood stream until it lodges. After lodging in the vessel, bloodflow is maintained due to the configuration of the device and itsanchoring structure. In another embodiment, an intracorporeal deviceincludes an anchoring structure that utilizes radial force to fix thedevice in the vessel. The radial force is released at a selected pointof deployment. Preferably the anchoring structure exerts the minimumradial force that will hold the intracorporeal device in place. Theradial force may also include the use of hooks or barbs to actively fixthe device. In a third embodiment, the intracorporeal device embolizeswithout an anchor mechanism. It could be preferable to eliminate theneed for a securing device and to allow the sensor to reside in a vesselthat is small enough to prevent further movement of the sensor. It issuspected that the small size of the sensor would have no deleteriouseffect on lung function due to the redundancy of blood flow in the lungsat the small vessel level.

One method of deploying and fixing an implant assembly according to thisinvention is described below. Access is gained into the vasculature anda vessel introducer is positioned in the access site. The access sitefor the vessel introducer may be the right internal jugular vein, thesubclavian artery, the right femoral vein, or any other suitable accesssite. A guidewire is placed in the vasculature and positioned across thedesired deployment site with the aid of, e.g., a Swan-Ganz catheter, adiagnostic catheter or any other suitable catheter, such catheter beingremoved after the guidewire is in position.

The delivery system is loaded into the vessel introducer and navigatedto the deployment site. The delivery system length can be increased ordecreased according to standard practice depending on the access sitechosen. In one embodiment, the deployment site is a vessel, and may beany artery or arteriole in the pulmonary artery vasculature. After theimplant assembly is oriented to a preferred orientation, the implantassembly is deployed by pulling the tether wire proximally to disengagethe implant assembly from the delivery apparatus. Upon deployment, theimplant assembly is allowed to “float” in the vasculature until itreaches a bifurcation in the vasculature. The anchoring mechanismprohibits the implant assembly from progressing into smaller vessels,thereby lodging the sensor at a location that is immediately proximal tothe bifurcation. The delivery assembly and guidewire are then removedfrom the body.

In an alternative embodiment of this method, an outer sleeve is providedto constrain an expansible structure so that sliding the outer sleeveproximally allows expansion of the expansible structure. If theexpansible structure is a radial wire array without hooks or barbs, theimplant assembly floats to the next bifurcation where it is lodged inplace exactly as described in the previous example. If the radial wirearray is quipped with hook or barb features, the implant assembly willremain fixed in the location at which it deployed. The delivery assemblyand guidewire are then removed from the body.

The embodiments described above may be employed with a wireless device,as shown in the Figures, or with a wired intracorporeal device.

Finally, it will be understood that the preferred embodiment has beendisclosed by way of example, and that other modifications may occur tothose skilled in the art without departing from the scope and spirit ofthe appended claims.

1. An implant assembly for deployment into a vessel at a location havingan inner diameter D1 and for lodging in the vessel at a downstreamlocation having a smaller inner diameter D2, the implant assemblycomprising: an intracorporeal device having a first end and a secondopposing end; at least one wire loop member comprising a deformable wirefixedly anchored to and extending outwardly longitudinally from at leastone end of the intracorporeal device and positionable in an operativeplane in a deployed position, wherein the deformable wire is configuredto resiliently contact and form an interference fit with a portion of awall of the vessel, and wherein, in the deployed position, the implantassembly has a diameter less than the inner diameter D1 but greater thanor equal to the inner diameter D2, wherein the intracorporeal device isadapted to be permanently fixed relative to the position of the createdinterference fit within the vessel.
 2. The implant assembly of claim 1,wherein the operative plane is substantially parallel to a longitudinalaxis of the intracorporeal device.
 3. The implant assembly of claim 1,wherein the intracorporeal device comprises a pressure sensor.
 4. Theimplant assembly of claim 1, wherein the at least one wire loop membercomprises a single wire having a double loop configuration, wherein thedouble loop configuration is positioned in the operative plane.
 5. Theimplant assembly of claim 1, wherein the at least one wire loop memberfurther comprises a first wire loop extending longitudinally from thefirst end of said intracorporeal device body.
 6. The implant assembly ofclaim 5, wherein the at least one wire loop member further comprises asecond wire loop extending longitudinally from the second end of saidintracorporeal device body.
 7. The implant assembly of claim 6, whereinthat first and second wire loops are substantially co-planar.
 8. Theimplant assembly of claim 1, wherein the intracorporeal device comprisesa coating and wherein the ends of the at least one wire loop member areinserted under the coating of the device to attach the at least one wireloop member to the intracorporeal device.
 9. The implant assembly ofclaim 1, wherein the implant assembly is at least partially radiopaque.10. The implant assembly of claim 1, wherein the implant assemblyfurther comprises a radiopaque marker.
 11. The implant assembly of claim1, wherein the at least one wire loop member is sufficiently stiff toprevent downstream movement of the implant assembly after theinterference fit is created.
 12. The implant assembly of claim 1,wherein the implant assembly obstructs less that 50% of thecross-sectional area of the inner diameter of the vessel into which theimplant assembly is positioned after the interference fit is created.13. The implant assembly of claim 1, wherein the at least one wire loopmember comprises a single wire having a double loop configuration, andwherein at least a central portion of the single wire is threadedthrough a hole defined in the intracorporeal device.
 14. The implantassembly of claim 1, wherein the vessel is a vessel of the human body.15. An implant assembly for deployment in a vessel, the implant assemblycomprising: an intracorporeal device, and a means for passively creatingan interference fit between the implant assembly and the inner diameterof the vessel at an operative location downstream of a release locationwithin the vessel, comprising at least one wire loop member configuredto extend outwardly longitudinally from at least one end of theintracorporeal device in an operative plane that is substantiallyparallel to a surface of the intracorporeal device when the at least onewire loop member is in a deployed position, wherein at least a portionof the at least one wire loop member is configured to yield to thevessel wall at the operative location, and wherein the intracorporealdevice is adapted to be permanently fixed relative to the operativelocation in the vessel.
 16. A method of deploying and fixing an implantassembly in a vessel, comprising: releasably mounting an implantassembly on a delivery apparatus in a delivery position, the implantassembly comprising: an intracorporeal device having a first end and asecond opposing end; and at least one wire loop member comprising adeformable wire fixedly anchored to and extending outwardlylongitudinally from at least one end of the intracorporeal device andpositionable in an operative plane in a deployed position, wherein thedeformable wire is configured to resiliently contact and form aninterference fit with a portion of a wall of the vessel; deploying theat least one wire loop member to the deployed position by separating theimplant assembly from the delivery apparatus at a release location inthe vessel having an inner diameter D1; passively creating aninterference fit between the deployed at least one wire loop member ofthe implant assembly, and the inner diameter of the vessel at anoperative location downstream of the release location within the vessel,wherein the intracorporeal device is adapted to be permanently fixedrelative to the position of the created interference fit within thevessel.
 17. The method of claim 16, wherein inner diameter of the vesselat an operative location downstream of the release location within thevessel has a inner diameter D2, and wherein, in the deployed position,the implant assembly has a diameter less than the inner diameter D1 butgreater than or equal to the inner diameter D2.
 18. The method of claim16, wherein the delivery apparatus comprises a catheter having a tetherwire.
 19. The method of claim 18, wherein the step of deploying furthercomprises: navigating the catheter and implant assembly to the releaselocation; and activating the tether wire to disengage the implantassembly from the catheter.
 20. The method of claim 19, furthercomprising removing the catheter from the body.